Methods and systems for liquid particle prequalification

ABSTRACT

Systems for prequalifying components for a processing chamber are described. The systems may be used to clean particulates from chamber parts and concurrently quantify the cleanliness. The systems may be used to qualify replacement parts before sending to a customer site for installation. The systems have three adjacent compartments separated by impermeable barriers. All three compartments are filled with liquid while cleaning a chamber component. The center compartment contains a submerged component for cleaning and qualifying. Two compartments on either side of the center compartment are configured with submerged ultrasonic transducers to deliver ultrasonic energy to either side of the component being cleaned and prequalified. A liquid pump is connected to the cleaning tub to recirculate water from the cleaning bath and another liquid pump is configured to remove a small amount of the cleaning bath to sample particulates.

FIELD

Embodiments described herein relate to determining cleanliness ofmanufacturing equipment and subcomponents.

BACKGROUND

In semiconductor substrate processing, the trend towards increasinglysmaller feature sizes and line-widths has placed a premium on theability to mask, etch, and deposit material on a semiconductor substratewith greater precision. As semiconductor features shrink, devicestructures become more fragile. Meanwhile, the killer defect size,defined as the particle size which renders the device non-functional,becomes smaller and more difficult to remove from the surface.Consequently, reducing device damage is one of the major drivers in thedevelopment of cleaning processes. As a result, this trend towardsincreasingly smaller feature sizes has placed a premium on thecleanliness of semiconductor manufacturing processes including thechamber component parts used in such processes.

Cleaning processes may be performed on chamber subcomponents andreplacement parts either at the customer site or at the primarysemiconductor manufacturing facility. Determining the cleanliness of thesubcomponents and replacement parts may be performed as a separateoperation prior to installation. The determination of cleanliness mayinvolve cleaning and qualification performed in separate equipment oreven separate facilities. This often undesirably involves transferringthe article from a cleaning tool into a separate analysis tool. Thesample may even be transferred to a separate facility or a separatecompany to perform analysis involved in qualification.

There is a need for an improved apparatus and process for cleaningchamber component parts that provide improved removal of particlecontaminants from chamber parts while significantly reducing any delayuntil the chamber part is qualified for end-use.

SUMMARY

Systems for prequalifying components for a processing chamber aredescribed. The systems may be used to clean particulates from chamberparts and concurrently quantify the cleanliness. The systems may be usedto qualify replacement parts before sending to a customer site forinstallation. The systems have three adjacent compartments separated byimpermeable barriers. All three compartments are filled with liquidwhile cleaning a chamber component. The center compartment contains asubmerged component for cleaning and qualifying. Two compartments oneither side of the center compartment are configured with submergedultrasonic transducers to deliver ultrasonic energy to either side ofthe component being cleaned and prequalified. A liquid pump is connectedto the cleaning tub to recirculate water from the cleaning bath andanother liquid pump is configured to remove a small amount of thecleaning bath to sample particulates.

Embodiments disclosed herein include an ultrasonic cleaning and samplingsystem. The systems include a cleaning tub. The systems further includea first ultrasonic tub and a second ultrasonic tub. The first ultrasonictub is disposed on the opposite side of the cleaning tub from the secondultrasonic tub. The systems further include a first impermeable barrierdisposed between the first ultrasonic tub and the cleaning tub. Thefirst impermeable barrier is configured to pass ultrasonic energy fromthe first ultrasonic tub into the cleaning tub when each of the firstultrasonic tub and the cleaning tub are filled with water. The systemsfurther include a second impermeable barrier disposed between the secondultrasonic tub and the cleaning tub. The second impermeable barrier isconfigured to pass ultrasonic energy from the second ultrasonic tub intothe cleaning tub when each of the second ultrasonic tub and the cleaningtub are filled with water. The systems further include a firstultrasonic transducer and a second ultrasonic transducer. The firstultrasonic transducer is in the first ultrasonic bath and the secondultrasonic transducer is in the second ultrasonic bath. The systemsfurther include an ultrapure water source configured to deliverultrapure water into the cleaning bath. The systems further include asampling pump fluidly coupled to the cleaning bath and configured toremove contaminated water from the cleaning bath. The systems furtherinclude a liquid particle counter fluidly coupled to the dilution unitand configured to measure the particle concentration of the contaminatedwater using optical scattering. The systems further include arecirculation pump fluidly coupled to the cleaning bath. The systemsfurther include a large particle filter fluidly coupled to therecirculation pump. The systems further include a small particle filterfluidly coupled to the large particle filter. A recirculation path isfluidly coupled to the cleaning bath at an outlet and an inlet. Therecirculation path includes the recirculation pump, the large particlefilter and the small particle filter.

The first ultrasonic transducer may be configured to be driven at afirst frequency greater than 20 kHz to produce cavitation in thecleaning tub. The first ultrasonic transducer and the second ultrasonictransducer may be configured to be driven at a same frequency toconcurrently produce cavitation in the cleaning tub. The firstultrasonic transducer may be configured to be driven at a firstmegasonic frequency to produce cavitation in the cleaning tub. Arecirculation pumping speed of the recirculation pump may be between 10liters/min and 200 liters/min. The first ultrasonic tub may beconfigured such that the first ultrasonic transducer is submersible. Thesmall particle filter may be selected to remove particles larger than 10nm while passing particles smaller than 10 nm. The large particle filtermay be selected to remove particles larger than 30 nm while passingparticles smaller than 30 nm. The recirculation path further maycomprise an ion-exchange filter.

Embodiments disclosed herein include an ultrasonic cleaning and samplingsystem. The systems include a cleaning tub. The systems further includea first ultrasonic tub and a second ultrasonic tub. The first ultrasonictub is disposed on the opposite side of the cleaning tub from the secondultrasonic tub. The systems further include a first impermeable barrierdisposed between the first ultrasonic tub and the cleaning tub. Thefirst impermeable barrier is configured to pass ultrasonic energy fromthe first ultrasonic tub into the cleaning tub when each of the firstultrasonic tub and the cleaning tub are filled with water. The systemsfurther include a second impermeable barrier disposed between the secondultrasonic tub and the cleaning tub. The second impermeable barrier isconfigured to pass ultrasonic energy from the second ultrasonic tub intothe cleaning tub when each of the second ultrasonic tub and the cleaningtub are filled with water. The systems further include a firstultrasonic transducer and a second ultrasonic transducer. The firstultrasonic transducer is in the first ultrasonic bath and the secondultrasonic transducer is in the second ultrasonic bath. The systemsfurther include an ultrapure water source configured to deliverultrapure water into the cleaning bath. The systems further include asampling pump fluidly coupled to the cleaning bath and configured toremove contaminated water from the cleaning bath. The systems furtherinclude a dilution unit fluidly coupled to the sampling pump andconfigured to dilute the contaminated water by a factor of at least 500.The systems further include a liquid particle counter fluidly coupled tothe dilution unit and configured to measure the particle concentrationof the contaminated water using optical scattering.

A sampling pumping speed of the sampling pump may be between 0.001milliliters/min and 10 milliliters/min. The dilution unit may beconfigured to dilute the contaminated water by a factor of at least 500by adding at least 500 times more ultrapure water from the ultrapurewater source. Each of the first impermeable barrier and the secondimpermeable barrier may be sheets of polypropylene, plastic, glass orquartz. The liquid particle counter is configured to detect particlesizes down to and including 100 nm.

Embodiments disclosed herein include methods of removing a contaminantfrom a surface of a part to-be-cleaned. the methods include placing thepart to-be-cleaned into a cleaning tub disposed between a firstultrasonic tub and a second ultrasonic tub. The methods further includefilling the cleaning tub with ultrapure water to form a cleaning bath.The methods further include filling the first ultrasonic tub and thesecond ultrasonic tub with water. The methods further include applyingultrasonic energy at a first frequency to a first ultrasonic transducerand at a second frequency to a second ultrasonic transducer. The firstultrasonic transducer is disposed within the first ultrasonic tub andthe second ultrasonic transducer is disposed within the secondultrasonic tub. The methods further include transmitting the ultrasonicenergy through the water across an impermeable barrier and into thecleaning bath. The methods further include removing the contaminant fromthe surface. The methods further include forming contaminated water byadding the contaminant to the cleaning bath. The methods further includeflowing the contaminated water into a liquid particle counter. Themethods further include determining a contamination concentration of thecontaminated water in the liquid particle counter. The contaminationconcentration may be compared to an endpoint contamination concentrationand the ultrasonic energy may be stopped if the contaminationconcentration is less than the endpoint contamination concentration.

To better understand the nature and advantages of the present invention,reference should be made to the following description and theaccompanying figures. It is to be understood, however, that each of thefigures is provided for the purpose of illustration only and is notintended as a definition of the limits of the scope of the presentinvention.

DESCRIPTION OF THE DRAWINGS

A further understanding of the nature and advantages of the disclosedtechnology may be realized by reference to the remaining portions of thespecification and the drawings.

FIG. 1A shows a system for cleaning and sampling components for asubstrate processing chamber according to embodiments.

FIG. 1B shows a system for cleaning and sampling components for asubstrate processing chamber according to embodiments.

FIG. 1C shows a system for cleaning and sampling components for asubstrate processing chamber according to embodiments.

FIG. 1D shows a system for cleaning and sampling components for asubstrate processing chamber according to embodiments.

FIG. 2 shows a method for cleaning and sampling components for asubstrate processing chamber according to embodiments.

FIG. 3 shows a close-up view of a system for cleaning and samplingcomponents for a substrate processing chamber according to embodiments.

FIG. 4 shows a top view of an exemplary substrate processing systemaccording to embodiments.

In the appended figures, similar components and/or features may have thesame reference label. Further, various components of the same type maybe distinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If only the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label.

DETAILED DESCRIPTION

Systems for prequalifying components for a processing chamber aredescribed. The systems may be used to clean particulates from chamberparts and concurrently quantify the cleanliness. The systems may be usedto qualify replacement parts before sending to a customer site forinstallation. The systems have three adjacent compartments separated byimpermeable barriers. All three compartments are filled with liquidwhile cleaning a chamber component. The center compartment contains asubmerged component for cleaning and qualifying. Two compartments oneither side of the center compartment are configured with submergedultrasonic transducers to deliver ultrasonic energy to either side ofthe component being cleaned and prequalified. A liquid pump is connectedto the cleaning tub to recirculate water from the cleaning bath andanother liquid pump is configured to remove a small amount of thecleaning bath to sample particulates.

FIG. 1A shows a system for cleaning and sampling components for asubstrate processing chamber according to embodiments. Any or allaspects of the embodiments depicted in each of FIGS. 1A, 1B, 1C, 1D maybe combined to form other embodiments. An ultrapure water (UPW) source140 is used to supply and/or replenish water to the cleaning tub ofsampling bath 101. Ultrapure water source 140 may include one, two ormore filtering stages, in embodiments, and generally will also include apolishing stage typically disposed following the filtering stages. Theone or more filtration stages are used to reduce particulateconcentration and the polishing stage is used to reduce theconcentration of ionized particulates, ionized minerals and ionizedorganic molecules. Ultrapure water, filtered water or unfiltered watermay be used to fill or replenish each of the ultrasonic baths 115 acontained in ultrasonic tubs 115 b in embodiments.

Sampling bath 101 comprises three compartments separated by impermeablebarriers 114. Impermeable barriers 114 do not allow water to passthrough but do transmit sound waves (e.g. ultrasonic energy, megasonicenergy or gigasonic energy). The center compartment is a spare part bath113 a in cleaning tub 113 b which is separated from an ultrasonic bath115 a in ultrasonic tub 115 b on either side by impermeable barriers114. Impermeable barriers 114 do not allow liquid, ions or particulatesto flow from spare part bath 113 to or from either of the two ultrasonicbaths 115 a in ultrasonic tubs 115 b in embodiments. Impermeablebarriers 114 impede all mass transport from either ultrasonic bath 115 ainto spare part bath 113 a according to embodiments. Each of spare parttub 113 b and ultrasonic tubs 115 b are equipped with drains (not shown)for quickly removing dumping cleaning bath 113 a and ultrasonic baths115 a and refilling with ultrapure water from ultrapure water source 140described previously. Alternatively, any water may be used to (re)fillultrasonic tubs 115 b since impermeable barriers 114 will not allowparticulates, ions or other contaminants to enter spare part bath 113 ain cleaning tub 113 b. In this description the chamber component beingcleaned and qualified may be referred to as a “spare part” but,generally speaking, the chamber component may be any part intended forinstallation onto a substrate processing chamber especially on theinterior of the chamber. The chamber component may be a refurbishedpart, a new spare part, an original part or any part, in embodiments,intended for use of a substrate processing chamber. Sampling bath 101 orthe walls of sampling bath 101 may comprise or consist of polypropylene,polyvinylidene fluoride (PVDF), polyethylene, glass or quartz inembodiments.

Spare part bath 113 a receives spare part 105 onto spare part support110 in the center compartment located between two ultrasonic baths 115a. Ultrapure water is prepared in ultrapure water source 140 and flowedinto cleaning tub 113 b. The ultrapure water may sometimes be referredto as UPW in the literature and may have a resistivity of above18.2MΩ-cm and total organic content (TOC) of below 5 ppb or between 1and 5 ppb in embodiments. The ultrapure water may only possessparticulates below 7 nm, below 5 nm or below 3 nm according toembodiments. The small size initially present in the ultrapure waterfacilitates the measurement of particles originating from spare part105. Cleaning tub 113 b may be filled before or after receiving sparepart 105 according to embodiments. Once spare part 105 and spare partbath 113 a are together, contaminants begin to detach from spare part105 and enter spare part bath 113 a. Contaminants (includingparticulates) may then be removed from cleaning tub 113 b and spare partbath 113 a by a variety of means described herein.

Contaminants may be removed from cleaning tub 113 b and spare part bath113, in part, by flowing through sampling pump 120 and a liquid particlecounter 130 according to embodiments before being flowed into the drain.Sampling pump 120 may be a peristaltic pump to accurately control theflow rate and to help ensure particles detected in liquid particlecounter 130 are primarily indicative of the cleanliness of spare part105. The liquid particle counter (LPC) may be configured with an opticalscattering system to detect particle sizes down to and including 30 nm,50 nm, 80 nm and/or 100 nm. The contaminated water is the ultrapurewater plus any contaminants which have been added from the partto-be-cleaned during the cleaning process. The contaminated water may beflowed into a drain after the concentration of the defects have beenmeasured.

Sampling bath 101 further includes two ultrasonic transducers 116 one ineach of the two ultrasonic baths 115 a in each of the two ultrasonictubs 115 b. One ultrasonic transducer 116 (as well as one ultrasonicbath 115 a/ultrasonic tub 115 b) are disposed on either side of sparepart bath 113. Positioning an ultrasonic transducer 116 on either sidehas been found to enhance the removal rate of particles from spare part105 during cleaning and prequalification. The cavitational energy iscreated in each of ultrasonic bath(s) 115 a and spare part bath 113 a inembodiments. One or both of ultrasonic transducers 116 are excited by afrequency greater than 20 kHz, greater than 40 kHz, greater than 60 kHz,greater than 80 kHz, greater than 100 kHz, greater than 200 kHz, greaterthan 500 kHz or greater than 1 MHz according to embodiments. Higherfrequencies have been found to correlate with reduced boundary layer andincreased particle removal probabilities. Reduced boundary layer andincreased particulate removal probabilities benefit the equipment andprocesses described herein. Typical ultrasonic transducers are operatedbelow 50 kHz which have been found to leave some particulates on sparepart 105 due to the larger boundary layer surrounding spare part 105.Megasonic frequencies are, generally, more effective at removingparticulates of interest as the frequency is increased towards and abovethe megahertz frequency region.

Impermeable barrier 114 may be a sheet of material which does not allowliquid to diffuse from one side to the other. Impermeable barrier 114may be a relatively thin sheet of material. Impermeable barrier 114 maybe a polypropylene, plastic, glass or quartz sheet according toembodiments. Impermeable barrier 114 may have a thickness of greaterthan 0.5 mm, greater than 1 mm or greater than 2 mm in embodiments.Impermeable barrier 114 may have a thickness of less than 20 mm, lessthan 10 mm or less than 5 mm in embodiments. Other aspects of theinvention will be described in the context of three further embodiments.

FIG. 1B shows a system for cleaning and sampling components for asubstrate processing chamber according to embodiments. An ultrapurewater (UPW) source 140 is used to supply and replenish water to samplingbath 101. Ultrapure water source 140 may include the componentsdescribed previously.

Sampling bath 101 again comprises three compartments separated byimpermeable barriers 114 which inhibit the flow of water but transmitsound waves (e.g. ultrasonic energy including megasonic and gigasonicenergy). Cleaning tub 113 b contains spare part bath 113 a and isseparated from an ultrasonic tub 115 b containing ultrasonic bath 115 aon either side by impermeable barriers 114 having properties describedearlier. Impermeable barriers 114 impede all mass transport from eitherultrasonic bath 115 a into spare part bath 113 a in embodiments. In thisdescription the chamber component to-be-cleaned and qualified may be aspare part, a refurbished part, an original part or any partto-be-cleaned. The part to-be-cleaned may ultimately be used in asubstrate processing chamber in embodiments.

Spare part bath 113 a receives spare part 105 onto spare part support110 in the center compartment located between two ultrasonic baths 115a. Ultrapure water is prepared in ultrapure water source 140 and flowedinto cleaning tub 113 b to form spare part bath 113 a. The ultrapurewater may have a resistivity of above 18.2MΩ-cm and total organiccontent (TOC) of below 5 ppb or between 1 and 5 ppb in embodiments. Theultrapure water may only possess particulates below 7 nm, below 5 nm orbelow 3 nm according to embodiments. The small size initially present inthe ultrapure water facilitates cleaning of spare part 105 and furtherfacilitates the measurement of particles originating from spare part105. Once spare part 105 and the ultrapure water are together,contaminants begin to depart from spare part 105 and may be removed fromspare part bath 113 a to quantify contamination.

Contaminants may be removed from spare part bath 113 a by a tube placednear the top of the waterline where particulates may preferentiallycollect. The tube may be placed within 10%, within 5% or within 3% ofthe top of spare part bath 113 a as measured relative to the meanwaterline of spare part bath 113 a. Contaminated water may be flowedthrough sampling pump 120 and a liquid particle counter 130 according toembodiments before being pumped into a drain as shown. Sampling pump 120may be a peristaltic pump to allow accurate and selectable control offlow rate at low flow volumes. Sampling pump 120 may be selected toensure particles detected in liquid particle counter 130 are indicativeof the cleanliness of spare part 105 in embodiments. Liquid particlecounter 130 may be configured with an optical scattering system todetect particle sizes down to and including 30 nm, 50 nm, 80 nm and/or100 nm according to embodiments.

Sampling bath 101 further includes two ultrasonic transducers 116 one ineach of the two ultrasonic baths 115 a. The term ultrasonic may be usedherein to encompass any frequency above 20 kHz and therefore includesmegasonic and gigasonic frequencies. Positioning one ultrasonictransducer 116 on either side of spare part bath 113 a has been found toenhance the removal rate of particles from spare part 105 duringcleaning and prequalification, especially when higher frequencies (>50kHz, megasonic and gigasonic) are used. higher frequencies benefit fromline-of-sight access to contaminated portions of spare part 105. Thecavitational energy is created in ultrasonic bath(s) 115 a and/or sparepart bath 113 a, in embodiments. One or both of ultrasonic transducers116 are excited by a frequency greater than 20 kHz, greater than 40 kHz,greater than 60 kHz, greater than 80 kHz, greater than 100 kHz, greaterthan 200 kHz, greater than 500 kHz or greater than 1 MHz according toembodiments. Higher cavitational frequencies correlate with a greaterprobability of dislodging particulates from spare part 105 over thefrequencies described herein. Impermeable barrier 114 may be a sheet ofmaterial which does not allow liquid to diffuse from one side to theother. Impermeable barrier 114 may be a plastic, glass or quartz sheet,in embodiments, and may have a thickness of greater than 0.5 mm, greaterthan 1 mm or greater than 2 mm in embodiments. In a preferredembodiment, the plastic sheet is a polypropylene sheet.

FIG. 1C shows a system for cleaning and sampling components for asubstrate processing chamber according to embodiments. An ultrapurewater (UPW) source 140 is used to supply and/or replenish water tosampling bath 101. Ultrapure water source 140 may include one, two ormore filtering stages, in embodiments, and generally will also include apolishing stage typically disposed following the filtering stages. Theone or more filtration stages are used to reduce particulateconcentration and the polishing stage is used to reduce theconcentration of ionized particulates, ionized minerals and ionizedorganic molecules.

Sampling bath 101 comprises three compartments separated by impermeablebarriers 114. Impermeable barriers 114 do not allow water to passthrough but do transmit sound waves at least in the ultrasonic frequencyrange. Spare part bath 113 a is separated from an ultrasonic bath 115 adisposed on either side by impermeable barriers 114. Impermeablebarriers 114 do not allow liquid, ions or particulates to flow fromeither of the two ultrasonic baths 115 a to spare part bath 113 a.Impermeable barriers 114 impede all mass transport from eitherultrasonic bath 115 a into spare part bath 113 a in embodiments. In allexamples described herein the chamber component being cleaned andqualified is referred to as a “spare part” but, generally speaking, thechamber component may be any part intended for installation onto asubstrate processing chamber especially on the interior of the chamber.

Spare part bath 113 a receives spare part 105 onto spare part support110 in the center compartment located between two ultrasonic baths 115 aas before. Ultrapure water is prepared in ultrapure water source 140 andflowed into cleaning tub 113 b to form spare part bath 113 a. Theultrapure water have a resistivity of above 18.2MΩ-cm and total organiccontent (TOC) of below 5 ppb or between 1 and 5 ppb in embodiments. Theultrapure water may only possess particulates below 7 nm, below 5 nm orbelow 3 nm according to embodiments. The small size initially present inthe ultrapure water facilitates the measurement of particles originatingfrom spare part 105. Once spare part 105 and the ultrapure water aretogether, contaminants begin to depart from spare part 105 and may beremoved from spare part bath 113 a.

Contaminants in the formerly ultrapure water (e.g. “contaminated water”)are removed from spare part bath 113 a by flowing through sampling pump120, a dilution system 125 and a liquid particle counter 130 accordingto embodiments prior to being dumped into a drain. Sampling pump 120 maybe a peristaltic pump to ensure a controlled reproducible low flow rate.Sampling pump 120 may be configured to control the flow rate to between0.001 ml/min and 10 ml/min, between 0.01 ml/min and 3 ml/min or between0.03 ml/min and 1 ml/min according to embodiments. As a consequence ofthe high sensitivity of some liquid particle counters 130 the water maybe diluted in dilution system 125 by a factor of 500× to 10,000× withwater from ultrapure water source 140. Diluting the water pumped bysampling pump 120 may reduce the chances of running into the saturationlimit of liquid particle counter 130. The water may be diluted bygreater than 500×, greater than 1,000×, greater than 2,000×, or greaterthan 3,000× according to embodiments. The liquid particle counter (LPC)may be configured with an optical scattering system to detect particlesizes down to and including 30 nm, 50 nm, 80 nm and/or 100 nm.

As before, sampling bath 101 further includes two ultrasonic transducers116 one in each of the two ultrasonic baths 115 a/ultrasonic tubs 115 b.Positioning one ultrasonic transducer 116 on either side of spare partbath 113 a/cleaning tub 113 b has been found to enhance the removal rateof particles from spare part 105 during cleaning and prequalification.The cavitational energy may be created in spare part bath 113 a inembodiments and may or may not be created in ultrasonic baths 115 a dueto the absence of a spare part. One or both of ultrasonic transducers116 are excited by a frequency greater than 20 kHz, greater than 40 kHz,greater than 60 kHz, greater than 80 kHz, greater than 100 kHz, greaterthan 200 kHz, greater than 500 kHz or greater than 1 MHz according toembodiments. Higher frequencies beneficially reduce the boundary layerthickness and beneficially increase particle removal probabilities.Impermeable barrier 114 may be a sheet of material which does not allowliquid to diffuse from one side to the other. Other aspects ofimpermeable barrier 114 have been described previously.

FIG. 1D shows a system for cleaning and sampling components for asubstrate processing chamber according to embodiments. An ultrapurewater (UPW) source 140 (not shown) is used to supply and replenish waterto sampling bath 101. The properties of the ultrapure water weredescribed previously.

Sampling bath 101 comprises three compartments separated by impermeablebarriers 114. Impermeable barriers 114 do not allow water to passthrough but do transmit sound waves (e.g. ultrasonic energy orfrequencies above 20 kHz). The center compartment is a cleaning bath 113a placed in a cleaning tub 113 b. Cleaning bath 113 a is separated froman ultrasonic bath 115 a on either side by impermeable barriers 114.Impermeable barriers 114 do not allow liquid, ions or particulates toflow from either of the two ultrasonic baths 115 a into cleaning bath113 a. Impermeable barriers 114 impede all mass transport from eitherultrasonic bath 115 a into cleaning bath 113 a in embodiments. In thisdescription the chamber component being cleaned and qualified may bereferred to as a “spare part” or more generally a part to-be-cleaned.

Cleaning bath 113 a receives spare part 105 onto spare part support 110in the center compartment located between two ultrasonic baths 115 a.Ultrapure water is prepared in ultrapure water source 140 and flowedinto cleaning tub 113 b to form cleaning bath 113 a. The ultrapure watermay only possess particulates below 7 nm, below 5 nm or below 3 nmaccording to embodiments. The small size initially present in theultrapure water facilitates the measurement of particles originatingfrom spare part 105. Cleaning tub 113 b may be filled before or afterreceiving spare part 105 according to embodiments. Once spare part 105and the ultrapure water are together, contaminants begin to leavesurfaces of spare part 105 and may additionally be removed from cleaningbath 113 a as follows.

Contaminants may be removed by recirculating the water within cleaningbath 113 a. The water may be flowed through a recirculation pump 150, aflowmeter 155 (optional), a large particle filter 160 and a smallparticle filter 165 according to embodiments. Optional flowmeter 155 maybe a non-contact flowmeter, in embodiments, to help limit theparticulates in cleaning bath 113 and limit the collection of totalorganic content (TOC) below the upper limits or within the rangesdescribed herein. Recirculation pump 150 may be a magnetically-coupledcentrifugal pump, in embodiments, to reduce the potential forintroducing defects which would be counterproductive. The water may flowthrough the recirculation pump 150, flowmeter 155 (optional), largeparticle filter 160 and small particle filter 165 in sequence accordingto embodiments. Flowmeter 155 may be a non-contact flowmeter to furtherimprove cleanliness and lengthen filter lifespan in embodiments. Largeparticle filter 160 may actually be two or more filters connected inparallel (not shown) in embodiments. According to embodiments, smallparticle filter 165 may analogously be a plurality of small particlefilters (not shown). The pumping speed of recirculation pump 150 may bebetween 10 liters/min and 200 liters/min, between 15 liters/min and 150liters/min or between 20 liters/min and 100 liters/min in embodiments.Recirculation pump 150 may be a seal-less magnetic drive pump accordingto embodiments. An ion-exchange filter may also be included at any pointin the recirculation path to increase the resistivity of the water backto or above 18.2MΩ-cm. The high resistivities recited herein have beenfound to increase the particulate cleanliness on the clean spare part105 by preventing metal-ion contamination which serve as particulatenucleation points.

Large particle filter 160 may only allow passage for particles below 30nm, below 20 nm or below 15 nm in embodiments. Small particle filter 165may only allow particles smaller than 10 nm, smaller than 7 nm, smallerthan 5 nm or smaller than 3 nm to pass through according to embodiments.The recited filter sizes allow the water to return to the initialparticle cleanliness present in the ultrapure water (UPW) generated inthe ultrapure water source 140.

An additional filter elements be included along the recirculation routeto further improve the cleaning efficiency and reduce the false-countrate registered in liquid particle counter 130. Bubbles in cleaning bath113 may be detected as particles in liquid particle counter 130 sinceoptical scattering detection techniques may scatter light from thesurface of a bubble in much the same way particle surfaces scatter thelight. Smaller bubbles (e.g. <50 nm) stay resident in liquids such ascleaning bath 113 for a long time. A degasser may be included to hastenthe removal of dissolved gases from cleaning bath 113 in embodiments.Degassers are available which remove up to 80% of the dissolved gasesfrom cleaning bath 113. Reducing dissolved air in cleaning bath 113removes a source of bubbles.

A pressurized sample collection chamber may be included in all theembodiments described herein. A small chamber continually collects waterfrom cleaning bath 113 at a pressure higher than a cleaning pressure ofcleaning bath 113. The elevated pressure in the pressurized samplecollection chamber drives out bubbles prior to measuring the particulateconcentration with liquid particle counter 130. The pressurized samplecollection chamber may be a region within liquid particle counter 130 ormay be a separate unit, according to embodiments. A debubbler mayfurther be included along the sampling path in embodiments. A debubblermay be connected between sampling pump 120 and liquid particle counter130 in all embodiments described herein according to embodiments.

All pumps, filters and other components in all recirculating or samplingpaths described herein may be selected to change the water in less thanten minutes, less than five minutes or less than three minutes accordingto embodiments. The flow rate or the refilling rate may independently begreater than 10 liters/min greater than 20 liters/min or greater than 30liters/min in embodiments. The size of cleaning tub 113 b and/orcleaning bath 113 a may be between 10 liters and 300 liters, between 20liters and 200 liters or between 50 liters and 150 liters according toembodiments. The size of either or each of ultrasonic baths 115 a orultrasonic tubs 115 b may be between 10 liters and 300 liters, between20 liters and 200 liters or between 50 liters and 150 liters inembodiments.

In all embodiments described herein, an impermeable barrier 114 may bedisposed between cleaning tub 113 b and ultrasonic tub 115 b.Impermeable barrier 114 may be in direct contact with cleaning bath 113a and ultrasonic bath 115 a in embodiments. The other borders ofcleaning bath 113 a and ultrasonic bath 115 a may be in contact withmore substantial materials which do not need to pass ultrasonic energy.The walls of sampling bath 101 may comprise polypropylene,polyvinylidene fluoride, glass or quartz. Put another way, ultrasonictub 115 b may comprise polypropylene, polyvinylidene fluoride, glass orquartz in embodiments. Similarly, cleaning tub 113 b may comprisepolypropylene, polyvinylidene fluoride, glass or quartz according toembodiments.

Contaminants may also depart from cleaning bath 113 a by flowing throughsampling pump 120, a dilution system 125 (optional) and a liquidparticle counter 130 according to embodiments prior to being flowed intothe drain. Sampling pump 120 may be a peristaltic pump to ensure acontrollable low flow rate and to ensure that particles detected inliquid particle counter 130 are primarily indicative of the cleanlinessof spare part 105. The liquid particle counter (LPC) may be configuredwith an optical scattering system to detect particle sizes down to andincluding 30 nm, 50 nm, 80 nm and/or 100 nm.

Sampling bath 101 may further include two ultrasonic transducers 116 onein each of the two ultrasonic baths 115. Positioning one ultrasonictransducer 116 on either side of cleaning bath 113 a/cleaning tub 113 bhas been found to enhance the removal rate of particles from spare part105 during cleaning and prequalification in embodiments. Thecavitational energy is created in each of ultrasonic bath(s) 115 a andcleaning bath 113 a in embodiments. One or both of ultrasonictransducers 116 are excited by a frequency greater than 20 kHz, greaterthan 40 kHz, greater than 60 kHz, greater than 80 kHz, greater than 100kHz, greater than 200 kHz, greater than 500 kHz or greater than 1 MHzaccording to embodiments. Higher frequencies correlate with reducedboundary layer and increased particle removal probabilities, each ofwhich benefit the equipment and processes described herein. Typicalultrasonic transducers are operated below 50 kHz which has been found toleave some particulates on spare part 105 due to the significantboundary layer surrounding spare part 105. Megasonic frequencies aretypically above 350 kHz and are progressively more effective at removingparticulates of interest as the frequency is increased into the (˜MHz)frequency region and beyond. Impermeable barrier 114 may have theproperties described previously.

FIG. 2 shows a method for cleaning and sampling components 201 for asubstrate processing chamber according to embodiments. The sampling bath101 is filled with ultrapure water in operation 210. Filling thesampling bath involves filling cleaning tub 113 b and ultrasonic tubs115 b with the ultrapure water. Spare part 105 is transferred intocleaning bath where it is supported by spare part support 110 (operation220). An RF signal of 80 kHz is applied to two ultrasonic transducersdisposed in two ultrasonic baths 115 a disposed on either side ofcleaning bath 113 a in operation 230. The immersion of spare part 105 inultrapure water in combination with the cavitation caused by theexcitation of the ultrasonic transducers dislodges particulates fromspare part 105 (operation 240). The dislodged particulates diffuse intocleaning bath 113 a. The dislodged particulates in combination with theultrapure water may be referred to as contaminated water herein. Thecontaminated water is pumped from cleaning bath 113 a (operation 250)and diluted with additional ultrapure water in selectable andpredictable proportions. The quantity of particulates in thecontaminated water is measured in a liquid particle counter 130 inoperation 260. Once the quantity of particulates in the contaminatedwater falls below a selectable threshold, the cleaning process may beterminated and spare part 105 may be removed from cleaning bath 113 aand cleaning tub 113 b.

FIG. 3 shows a close-up view of a system for cleaning and samplingcomponents for a substrate processing chamber according to embodiments.FIG. 3 is a close-up of a cleaning event inside cleaning bath 113 a. Aspare part portion 305 of spare part 105 is shown with an attachedparticle 308 which is to be removed using ultrasonic agitation. Typicalultrasonic frequencies lie in the 20 kHz to 40 kHz range and may resultin a large boundary layer (e.g. 2.5 μm) compared to current “killer”particle sizes which negatively impact semiconductor device yield. Thesizes of killer particles becomes smaller and smaller as semiconductorlinewidths are reduced. Using ultrasonic frequencies in the range from50 kHz to 300 kHz (e.g. 80 kHz) reduces the boundary layer thickness(e.g. 0.5 μm in the figure) which facilitates the disturbance ofparticle 308 by the ultrasonic energy. The boundary layer remains morestationary compared to regions outside the boundary layer since the masstransport in the layer is dominated by the stationary surface of sparepart portion 305. The reduced thickness of the boundary layer enablesparticle 308 to become dislodged and flow away from the surface intocleaning bath portion 313 and later pass sampling pump 120 before beinganalyzed in liquid particle counter 130.

Process flows may ordinarily involve cleaning and checking thecleanliness of spare in separate equipment and even separate facilitieswhich reduces the sampling frequency and increases costs. Implementingthe hardware and processes described herein offers the benefit ofreducing costs, increasing the number of (e.g. spare) parts sampled, andincreasing process simplicity afforded by cleaning and quantifyingdefectivity in the same equipment or in the same vessel in embodiments.The sampling bath may be installed at the manufacturing plant, anintermediate facility or at the destination semiconductor manufacturingsite to increase flexibility. A benefit of the simplified process flowincludes a reduction of the opportunity of introducing contamination tothe part to-be-cleaned during handling and transportation stages. Afurther benefit of the processes and hardware described herein includein-process monitoring which allows the end-point of the cleaning processto be determined as the spare part is cleaned.

During the cleaning processes described herein, cleaning bath 113 a maybe at a temperature between 10° C. and 90° C., between 20° C. and 80°C., or between 25° C. and 50° C. according to embodiments. Ultrasonicbaths (115 a) may be at the same temperature as cleaning bath 113 a inembodiments. Ultrasonic baths (115 a) may be at an ultrasonic bathtemperature between 10° C. and 90° C., between 20° C. and 80° C. orbetween 25 and 50° C., according to embodiments. Cleaning bath 113 a maybe at a temperature greater than 15° C., greater than 20° C., greaterthan 25° C., or greater than 30° C. in embodiments. Higher temperaturesfor cleaning bath 113 a have been found to correlate with a greaterremoval efficiency of particulates from spare part 105 according toembodiments. Ultrasonic baths 115 a may be at a temperature greater than15° C., greater than 20° C., greater than 25° C., or greater than 30° C.in embodiments. The temperature will rise simply by the introduction ofcavitational energy to the cleaning bath 113 a and ultrasonic baths 115a. A resistive heater may not be included or may be included accordingto embodiments to achieve higher temperatures of the baths. Cleaningbath 113 a and ultrasonic baths 115 a may comprise mostly the same orthe same type of fluid and may comprise mostly water or water of avariety of purities according to embodiments.

FIG. 4 shows a substrate processing system 1201 of deposition, etching,baking, and curing chambers. Each chamber may contain components andspare parts which can be cleaned using the systems described herein,according to embodiments. In the figure, a pair of front opening unifiedpods (load lock chambers 1202) supply substrates of a variety of sizesthat are received by robotic arms 1204 and placed into a low pressureholding area 1206 before being placed into one of the substrateprocessing chambers 1208 a-f. A second robotic arm 1210 may be used totransport the substrate wafers from the holding area 1206 to thesubstrate processing chambers 1208 a-f and back. Each substrateprocessing chamber 1208 a-f, can be outfitted to perform a number ofsubstrate processing operations including the dry etch processesdescribed herein in addition to cyclical layer deposition (CLD), atomiclayer deposition (ALD), chemical vapor deposition (CVD), physical vapordeposition (PVD), etch, pre-clean, degas, orientation, and othersubstrate processes.

As used herein “substrate” may be a support substrate with or withoutlayers formed thereon. The patterned substrate may be an insulator or asemiconductor of a variety of doping concentrations and profiles andmay, for example, be a semiconductor substrate of the type used in themanufacture of integrated circuits.

Having disclosed several embodiments, it will be recognized by those ofskill in the art that various modifications, alternative constructions,and equivalents may be used without departing from the spirit of thedisclosed embodiments. Additionally, a number of well-known processesand elements have not been described to avoid unnecessarily obscuringthe present embodiments. Accordingly, the above description should notbe taken as limiting the scope of the claims.

Where a range of values is provided, it is understood that eachintervening value, to the tenth of the unit of the lower limit unlessthe context clearly dictates otherwise, between the upper and lowerlimits of that range is also specifically disclosed. Each smaller rangebetween any stated value or intervening value in a stated range and anyother stated or intervening value in that stated range is encompassed.The upper and lower limits of these smaller ranges may independently beincluded or excluded in the range, and each range where either, neitheror both limits are included in the smaller ranges is also encompassedwithin the claims, subject to any specifically excluded limit in thestated range. Where the stated range includes one or both of the limits,ranges excluding either or both of those included limits are alsoincluded.

As used herein and in the appended claims, the singular forms “a”, “an”,and “the” include plural referents unless the context clearly dictatesotherwise. Thus, for example, reference to “a process” includes aplurality of such processes and reference to “the dielectric material”includes reference to one or more dielectric materials and equivalentsthereof known to those skilled in the art, and so forth.

Also, the words “comprise,” “comprising,” “include,” “including,” and“includes” when used in this specification and in the following claimsare intended to specify the presence of stated features, integers,components, or steps, but they do not preclude the presence or additionof one or more other features, integers, components, steps, acts, orgroups.

1. An ultrasonic cleaning and sampling system, comprising: a cleaningtub; a first ultrasonic tub and a second ultrasonic tub, wherein thefirst ultrasonic tub is disposed on the opposite side of the cleaningtub from the second ultrasonic tub; a first impermeable barrier disposedbetween the first ultrasonic tub and the cleaning tub, wherein the firstimpermeable barrier is configured to pass ultrasonic energy from thefirst ultrasonic tub into the cleaning tub when each of the firstultrasonic tub and the cleaning tub are filled with water; a secondimpermeable barrier disposed between the second ultrasonic tub and thecleaning tub, wherein the second impermeable barrier is configured topass ultrasonic energy from the second ultrasonic tub into the cleaningtub when each of the second ultrasonic tub and the cleaning tub arefilled with water; a first ultrasonic transducer and a second ultrasonictransducer, wherein the first ultrasonic transducer is in the firstultrasonic bath and the second ultrasonic transducer is in the secondultrasonic bath; an ultrapure water source configured to deliverultrapure water into the cleaning bath; a sampling pump fluidly coupledto the cleaning bath and configured to remove contaminated water fromthe cleaning bath; a liquid particle counter fluidly coupled to thedilution unit and configured to measure the particle concentration ofthe contaminated water using optical scattering; a recirculation pumpfluidly coupled to the cleaning bath; a large particle filter fluidlycoupled to the recirculation pump; and a small particle filter fluidlycoupled to the large particle filter, wherein a recirculation pathconnects to the cleaning bath at an outlet and an inlet and therecirculation path comprises the recirculation pump, the large particlefilter and the small particle filter.
 2. The ultrasonic cleaning andsampling system of claim 1 wherein the first ultrasonic transducer isconfigured to be driven at a first frequency which is greater than 20kHz to produce cavitation in the cleaning tub.
 3. The ultrasoniccleaning and sampling system of claim 1 wherein the first ultrasonictransducer and the second ultrasonic transducer are configured to bedriven at a same frequency to concurrently produce cavitation in thecleaning tub.
 4. The ultrasonic cleaning and sampling system of claim 1wherein the first ultrasonic transducer is configured to be driven at afirst megasonic frequency to produce cavitation in the cleaning tub. 5.The ultrasonic cleaning and sampling system of claim 1 wherein arecirculation pumping speed of the recirculation pump is between 10liters/min and 200 liters/min.
 6. The ultrasonic cleaning and samplingsystem of claim 1 wherein the first ultrasonic tub is configured suchthat the first ultrasonic transducer is submersible.
 7. The ultrasoniccleaning and sampling system of claim 1 wherein the small particlefilter is selected to remove particles larger than 10 nm while passingparticles smaller than 10 nm.
 8. The ultrasonic cleaning and samplingsystem of claim 1 wherein the large particle filter is selected toremove particles larger than 30 nm while passing particles smaller than30 nm.
 9. The ultrasonic cleaning and sampling system of claim 1 whereinthe recirculation path further comprises an ion-exchange filter.
 10. Anultrasonic cleaning and sampling system, comprising: a cleaning tub; afirst ultrasonic tub and a second ultrasonic tub, wherein the firstultrasonic tub is disposed on the opposite side of the cleaning tub fromthe second ultrasonic tub; a first impermeable barrier disposed betweenthe first ultrasonic tub and the cleaning tub, wherein the firstimpermeable barrier is configured to pass ultrasonic energy from thefirst ultrasonic tub into the cleaning tub when each of the firstultrasonic tub and the cleaning tub are filled with water; a secondimpermeable barrier disposed between the second ultrasonic tub and thecleaning tub, wherein the second impermeable barrier is configured topass ultrasonic energy from the second ultrasonic tub into the cleaningtub when each of the second ultrasonic tub and the cleaning tub arefilled with water; a first ultrasonic transducer and a second ultrasonictransducer, wherein the first ultrasonic transducer is in the firstultrasonic bath and the second ultrasonic transducer is in the secondultrasonic bath; an ultrapure water source configured to deliverultrapure water into the cleaning bath; a sampling pump fluidly coupledto the cleaning bath and configured to remove contaminated water fromthe cleaning bath; a dilution unit fluidly coupled to the sampling pumpand configured to dilute the contaminated water by a factor of at least500; and a liquid particle counter fluidly coupled to the dilution unitand configured to measure the particle concentration of the contaminatedwater using optical scattering.
 11. The ultrasonic cleaning and samplingsystem of claim 10 wherein a sampling pumping speed of the sampling pumpis between 0.001 milliliters/min and 10 milliliters/min.
 12. Theultrasonic cleaning and sampling system of claim 10 wherein the dilutionunit is configured to dilute the contaminated water by a factor of atleast 500 by adding at least 500 times more ultrapure water from theultrapure water source.
 13. The ultrasonic cleaning and sampling systemof claim 10 wherein each of the first impermeable barrier and the secondimpermeable barrier are sheets of polypropylene, plastic, glass orquartz.
 14. The ultrasonic cleaning and sampling system of claim 10wherein the liquid particle counter is configured to detect particlesizes down to and including 100 nm.
 15. A method of removing acontaminant from a surface of a part to-be-cleaned, the methodcomprising: placing the part to-be-cleaned into a cleaning tub disposedbetween a first ultrasonic tub and a second ultrasonic tub; filling thecleaning tub with ultrapure water to form a cleaning bath; filling thefirst ultrasonic tub and the second ultrasonic tub with water; applyingultrasonic energy at a first frequency to a first ultrasonic transducerand at a second frequency to a second ultrasonic transducer, wherein thefirst ultrasonic transducer is disposed within the first ultrasonic tuband the second ultrasonic transducer is disposed within the secondultrasonic tub; transmitting the ultrasonic energy through the wateracross an impermeable barrier and into the cleaning bath; removing thecontaminant from the surface; forming contaminated water by adding thecontaminant to the cleaning bath; flowing the contaminated water into aliquid particle counter; and determining a contamination concentrationof the contaminated water in the liquid particle counter.
 16. The methodof removing a contaminant from a surface of a part to-be-cleaned ofclaim 15 wherein the contamination concentration is compared to anendpoint contamination concentration and the ultrasonic energy isstopped if the contamination concentration is less than the endpointcontamination concentration.